Process for automatically co-ordinating the filling operation of shift elements

Abstract

A process is proposed for automatically coordinating the filling and feeding operation of hydraulically operated and hydraulically or electronically individually commanded shift elements. The filling and feeding operation is divided into a rapid filling phase and a filling equalization phase and has as parameters at least one rapid filling period, one rapid filling pressure, one filling equalization period and one filling equalization pressure. To optimize said parameters two of the four are preset and for the other two, an optimal value is determined for the first parameter to be optimized on the basis of a preset, time-dependent pressure curve in which a pressure increase phase follows the rapid filling phase and equalization phase. To this end, based on an initial value presettable in each case, the first parameter is gradually adjusted until a speed change occurs at or before the start of the pressure increase phase. For the other parameter to be optimized, at the optimal value of the first parameter to be optimized and based on the respective presettable initial value, said parameter is gradually changed until a speed change occurs before or at least approximately simultaneously with the start of the pressure increase phase.

What is claimed is: 
     
       1. A process for automatically coordinating the filling and feeding operation of hydraulically operated and hydraulically or electronically individually commanded shift elements, the filling and feeding operation of which takes place according to a time-dependent pressure curve with a rapid filling phase (SFP), a filling equalization phase (FAP) and a pressure increase phase (DAP) and as parameters are used at least a rapid filling time (T --  SF), a rapid filling pressure (p --  SF), a filling equalization period (T --  FA) and a filling equalization pressure (p --  FA), characterized in that to optimize the parameters (T --  SF, p --  SF, T --  FA, p --  FA), two parameters are preset and for the other two parameters within a time-dependent pressure curve, an optimal value (p --  FA,opt, T --  FA,opt, p --  SF,opt, T --  SF,opt) of the first parameter to be optimized is determined in a manner such that based on an appropriate presettable initial value (p --  FA,a, T --  FA,a, p --  SF,a, T --  SF,a), said value is changed gradually until a speed change occurs with the start of the pressure increase phase (DAP) and the other parameter to be optimized is determined by gradually changing it at the optimal value (p --  FA,opt, T --  FA,opt, p --  SF,opt, T --  SF,opt) of the first parameter to be optimized and based on the appropriate presettable initial value (p --  FA,a, T --  FA,a, p --  SF,a, T --  SF,a) until a speed change occurs at least approximately simultaneously with the start of the pressure increase phase DAP. 
     
     
       2. The process according to claim 1, wherein the presettable initial values (P --  FA,a, T --  FA,a, p --  SF,a, T --  SF,a) are each empirically determined limiting values (p --  FA,max, T --  FA,max, p --  SF,max, T --  SF,max). 
     
     
       3. The process according to claim 1 wherein the shift element or the control thereof is detected to be defective when a) while increasing a parameter value for determining the respective optimal value (p --  FA,opt, T --  FA,opt, p --  SF,opt, T --  SF,opt) after start of the pressure increase phase (DAP), no speed change occurs and/or   b) the determine optimal value (p --  FA,opt, T --  FA,opt, p --  SF,opt, T --  SF,opt) is outside a respective empirically determined tolerance range (p --  FA,min, T-FA,min, p --  SF,min, T --  SF,min).   
     
     
       4. The process according to claim 1 wherein when the respective shift element is closed, a measurable speed change clearly coordinatable with said shift element occurs. 
     
     
       5. The process according to claim 1 wherein the speed change is detected by a divergence of the speed from a mean value and/or by formation of a speed gradient. 
     
     
       6. The process according to claim 1 wherein said parameters (T --  SF, p --  SF, T --  FA, p --  FA) are optimized at a defined transmission temperature. 
     
     
       7. The process according to claim 1 wherein the preset two of the four parameters (T --  SF, p --  SF, T --  FA, p --  FA) are empirically determined. 
     
     
       8. The process according to claim 1 wherein the value of said rapid filling pressure (p --  SF) is selected so as to be above the filling equalization pressure (p --  FA) by a pre-defined amount. 
     
     
       9. The process according to claim 1 wherein for optimizing the parameters (T --  SF, p --  SF, T --  FA, p --  FA), the speed of an engine interacting with the shift elements is raised until an influence of the system pressure is eliminated. 
     
     
       10. The process according to claim 1 wherein a transmission output interacting with the shift elements is blocked during the optimization of the parameters.